GitHub user jianqiao opened a pull request:
https://github.com/apache/incubator-quickstep/pull/332
Small adjustments in star schema cost model for # distinct values estimation
This PR has a small adjustment in star schema cost model for # of distinct
values estimation, together with a fix to a potential bug with
`impliesUniqueAttributes`.
The adjustment is likely to improve query plans _when table stats are not
present_. It does not affect SSB/TPC-H performance.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/jianqiao/incubator-quickstep adjust-cost
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/incubator-quickstep/pull/332.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #332
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commit 8e94a8e7ef6c99e5c64d1d96bb7283f9f1154116
Author: Jianqiao Zhu <jianqiao@...>
Date: 2018-02-07T21:42:15Z
Small adjust in star schema cost model for # distinct values
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